In the past, black-and-white printing papers and color printing papers have been obtained by coating silver halide emulsion layers and protective layers on a reflective supports (for example, on baryta papers or resin coated papers) which have been made by mixing white pigments obtained by powdering transparent inorganic materials having a high refractive index with a sizing agent in a white base paper or by dispersing such pigments in a plastic film.
Photographic photosensitive materials in which simple mixed layers of microcapsules containing silver halide emulsions which have different optical wavelengths are coated onto aluminum supports having a mirror surface, i.e., a metallic luster, have been described in the specification of JP-A-49-33783 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application"). Examples of color printing papers in which supports which have metal foils which have non-directional matt glazed surfaces with resin layers over the top are used have been disclosed in the specification of JP-A-62-21147.
Generally, the reflection on the surfaces of substances are usually roughly classified into a mirror reflection and diffuse reflection. Further, the diffuse reflection can be classified into the primary diffuse reflection property and the secondary diffuse reflection property. The mirror reflection is the reflection on a smooth surface in accordance with the regular reflection law. The diffuse reflection is observed on the surfaces of papers, coatings, woods and walls, wherein incident light reflects not only regularly but also irregularly on the surface.
The secondary diffuse reflection property is observed on all the surfaces having minute slant boundaries such as the surface of a ground glass or abraded metal surface. The term "secondary diffuse reflection property" herein indicates a reflection occurring on a smooth mirror surface but on which very small unevennesses are provided to form boundaries thereon. The diffuse reflected light can be deemed as a collection of regularly reflected lights on the respective very small reflection surfaces. This is why the secondary diffuse reflection property is called "reflection property on small mirror planes" as defined in chapter 18, section 1 in Shikisai Kagaku Handbook, 5th Ed., edited by Japanese Color Society and published by Tokyo University Publishing Co. in 1985.
The primary diffuse reflection property is generally distinguished from the secondary diffuse reflection by the difference of the surface diffuse reflectance on the mirror surface of the substances. Generally, the reflectance of the substances having the primary diffuse reflection property is lower than that of the substances having the secondary diffuse reflection. The term "primary diffuse reflection" means that when a light-transmitting solid is finely pulverized and irradiated with a light, the incident light is diffused by the total reflection or the reflection on a part of the surface.
Furthermore, supports which have mirror surface reflection properties or secondary diffuse reflection properties, as defined, for example, in chapter 18, section 1 in Shikisai Kagaku Handbook (Japanese Color Society, 5th Edition, 1985, published by Tokyo University Publishing Co.) have been described, for example, in JP-A-61-210346, JP-A-63-118154, JP-A-63-24247, JP-A-63-24251, JP-A-63-24252, JP-A-63-24253, JP-A-63-24255 and JP-A-63-70844. However, in supports which have a resin layer over a metal surface of this type, the edge adhesion with overlying silver halide photosensitive layers or intermediate layers is poor. On the other hand, if the metal which forms the reflective surface is a metal such as aluminum which is less noble than silver, the metal may be dissolved out during processing and reduce the activity of the processing baths, and problems can arise with the occurrence of fogging and spotting.
With color photosensitive materials in which high luster metal supports are used, during processing, the processing solutions permeate from cut surfaces or from the edges and the film is liable to peel away, especially where the part which forms the surface of the support is a metal such as aluminum or an alloy thereof. Such film peeling cannot be prevented satisfactorily by providing a thermoplastic resin layer between the metal surface and the emulsion layers. Furthermore, such impregnating processing solutions are difficult to wash out satisfactorily prior to the completion of processing and staining is liable to develop with aging. Furthermore, strong coloration and tarring are liable to occur (edge staining).
Printed photographs made on color photosensitive materials which have a photosensitive layer in which a high luster metal support is used and which, in particular, have a photosensitive layer containing fine particles dispersed within it, with an oil or polymer as a dispersing agent, provide images which have especially good sharpness and saturation, etc., and so these defects (i.e., strong coloration, tarring, etc.) are particularly noticeable.
Furthermore, processing variations, such as fogging and softening of gradation, are increased when these color photosensitive materials are subjected to continuous color processing together with color papers in which ordinary (with primary diffuse reflection properties) reflective supports are used.
Various means are required for solving these problems, which arise on color development processing when special supports according to the present invention are used.